Year of Publication


Degree Name

Master of Science (MS)

Document Type

Master's Thesis


Agriculture, Food and Environment


Plant and Soil Sciences

First Advisor

Dr. Erin Haramoto


The importance of sustainable weed management practices continues to grow as farmers are increasingly faced with herbicide resistant weed populations. Marestail (Conyza canadensis), also known as horseweed, is a problematic weed in soybean cropping systems that has developed resistance to multiple herbicide modes of action. A two year study was conducted in Lexington, KY, examining timing patterns of marestail emergence and different integrated weed management strategies for marestail prior to no-till soybean. Treatments contained fall and spring applied herbicides with different levels of residual activities, cover crops and combinations of the two. Additionally, yields and partial budget net returns of each management strategy were compared to a resistance weed management treatment and a common weed management program that many soybean farmers are employing. Excluding the control population in year one, in both site years, marestail emergence was significantly higher during the fall in all populations. Treatments containing a cover crop suppressed marestail emergence equivalently to treatments using herbicides in both years. There were no significant differences in yields when a cover crop was present in either year. Partial budget net returns varied in treatments using cover crops and synthetic herbicides. A treatment using a cover crop had the highest net returns in both years.

Digital Object Identifier (DOI)

Funding Information

U.S. Department of Agriculture National Institute of Food and Agriculture award number 2017-70006-27265, awarded 2017.

U.S. Department of Agriculture National Institute of Food and Agriculture award number 2017-38640-26914, subaward SUB00001840, awarded 2018 (immediately through Southern Sustainable Agriculture Research and Education).